Design and photocatalytic performance of BaFe₁₂O₁₉ nanoplatelets for RR195 dye

The synthesis of single-phase magneto-plumbite (M−type) Ba-hexaferrite (BaFe₁₂O₁₉) remains challenging, particularly at nano scale. This study investigates the formation of pure BaFe₁₂O₁₉ via sol–gel autocombustion (SGA) and coprecipitation (CP) methods, using a stoichiometric Ba/Fe ratio (1/12) and annealing between 650–950 °C. Six (SGA) and four (CP) samples were prepared. Rietveld refinement of X-ray diffraction patterns confirmed single-phase BaFe₁₂O₁₉ with 73(6) nm crystallite size at 950 °C using the SGA route (R12-SGA3). Transmission electron microscopy analysis revealed nanoplatelet morphology with low agglomeration and good dispersion. Photocatalytic performance, optimized using Box–Behnken design, showed 97% degradation of reactive red 195 dye under visible light at optimal conditions: 0.89 g L^–1 catalyst dose, 1.03 h irradiation, and 10.03 mg L^–1 dye concentration. The model exhibited strong correlation (R² = 0.944), validating the optimization. The BaFe₁₂O₁₉ catalyst also exhibited excellent reusability, maintaining > 90% efficiency after four cycles, indicating its promise for environmental remediation applications.